3SEB

STAPHYLOCOCCAL ENTEROTOXIN B

Summary for 3SEB

• Entry DOI: 10.2210/pdb3seb/pdb
• Descriptor: STAPHYLOCOCCAL ENTEROTOXIN B (2 entities in total)
• Functional Keywords: toxin, superantigen, enterotoxin
• Biological source: Staphylococcus aureus
• Cellular location: Secreted: P01552
• Total number of polymer chains: 1
• Total formula weight: 28281.88

Authors

Papageorgiou, A.C.,Acharya, K.R. (deposition date: 1997-11-26, release date: 1998-05-27, Last modification date: 2024-04-03)

Primary citation

Papageorgiou, A.C.,Tranter, H.S.,Acharya, K.R.
Crystal structure of microbial superantigen staphylococcal enterotoxin B at 1.5 A resolution: implications for superantigen recognition by MHC class II molecules and T-cell receptors.
J.Mol.Biol., 277:61-79, 1998

PubMed Abstract: Staphylococcal enterotoxin B is a member of a family of toxins known as superantigens that activate a large number of T-cells (up to 20%) by cross-linking MHC class II molecules with T-cell receptors in a Vbeta-restricted fashion. The crystal structure of staphylococcal enterotoxin B presented here has been determined at 1.5 A resolution, the highest resolution so far for a superantigen. The final model contains 1948 protein atoms and 177 water molecules and has excellent geometry with root-mean-square (rms) deviation of 0.007 A and 1.73 degrees in bond lengths and bond angles, respectively. The overall fold is similar to that of other microbial superantigens, but as it lacks the zinc-binding site found in other members of this family, such as staphylococcal enterotoxin A, C2 and D, this enterotoxin possesses only one MHC class II binding site. Comparison of the crystal structure of free SEB and in complex with an MHC class II molecule revealed no major changes in the MHC-binding site upon complex formation. However, a number of water molecules found in the free SEB may be displaced in the complex or contribute further to its stability. Detailed analysis of the TcR-binding site of SEB, SEA and SEC2 shows significant differences which may account for the ability of each superantigen to bind specific Vbeta sequences.

PubMed: 9514739
DOI: 10.1006/jmbi.1997.1577

Experimental method

X-RAY DIFFRACTION (1.48 Å)